This application is based on and claims priority to Japanese Patent Application No. 2000-19276, filed Jun. 28, 2000.
1. Field of the Invention
This invention relates generally to an exhaust system for a watercraft, and more particularly to an improved exhaust silencer for the exhaust system.
2. Description of Related Art
Personal watercrafts have become very popular in recent years. This type of watercraft is quite sporting in nature and carries one or more riders. A hull of the watercraft typically defines a rider""s area above an engine compartment. An internal combustion engine powers a jet propulsion unit that propels the watercraft by discharging water rearward. The engine lies within the engine compartment in front of a tunnel which is formed on an underside of the hull. The jet propulsion unit is placed within the tunnel and includes an impeller that is driven by the engine.
The watercraft is provided with an exhaust system to route exhaust gases from the engine to a location out of the watercraft. In a typical arrangement, the exhaust system comprises exhaust conduits connected in series and the last conduit opens to the tunnel to discharge the exhaust gases thereto. One of the exhaust components forms a silencer to reduce exhaust noise. A body of the silencer typically is configured as a cylindrical shape structure. Usually, an inlet conduit is coupled with the body adjacent to a front end surface thereof, while an outlet conduit is coupled with the body toward an aft end of the silencer body. In some layouts of the personal watercraft, such an arrangement is not available or is not convenient due to surrounding device configurations or arrangements. For example, the outlet conduit must be placed in close proximity to the inlet conduit in one occasion. In this arrangement, however, another problem can arise in connection with the following special circumstances of the watercraft. That is, the outlet conduit preferably extends generally upwardly from the silencer body because outside water can be surely inhibited from entering the silencer body. In the meantime, normally, this type of watercraft includes a water cooling system to cool at least the engine with water, and the exhaust system allows the water to be delivered to the silencer body with the exhaust gases. In order to drive the water in the silencer body out, an inside end of the outlet conduit preferably is placed at the lowermost position within the silencer body. If, however, the outlet conduit must be placed adjacent to the inlet conduit, both the conduits (i.e., the conduits themselves and/or exhaust flows coming in and going out through the conduits) can interfere with each other within the silencer body.
A need therefore exists for an improved exhaust system of a watercraft that can have a construction of a silencer in which inlet and outlet conduits are arranged without interfering with each other.
In accordance with one aspect of the present invention, a watercraft comprises an internal combustion engine. An exhaust system is arranged to route exhaust gases from the engine to a location external of the watercraft. The exhaust system includes an exhaust silencer. An inlet conduit is arranged to deliver the exhaust gases to the silencer. An outlet conduit is arranged to discharge the exhaust gases from the silencer. The silencer comprises a main body defining a first chamber. The inlet conduit is coupled with the main body to communicate with the first chamber. A side body extends to a side of the main body. The side body defines a second chamber communicating with the first chamber. The outlet conduit is coupled with the side body to communicate with the second chamber.
In accordance with another aspect of the present invention, a watercraft comprises an internal combustion engine. An exhaust system is arranged to route exhaust gases from the engine to a location external from the watercraft. The exhaust system includes an exhaust silencer. An inlet conduit is arranged to deliver the exhaust gases to the silencer. An outlet conduit is arranged to discharge the exhaust gases from the silencer. The silencer comprises first and second body members coupled with one another. The first body member defines a first chamber. The second body member defines a second chamber communicating with the first chamber. The inlet conduit is connected to the first chamber. The outlet conduit is connected to the second chamber. A lowermost point of the second body member is lower than a lowermost point of the first body member.
In accordance with yet another aspect of the present invention, an exhaust silencer for an engine comprises a first outer housing containing a first internal volume and a partition dividing the internal volume into at least first and second chambers. The first chamber is defined between a first wall and the partition. An inlet conduit extends through the first wall into the first chamber. A first plane extends through the partition and a second plane extends through the first wall, generally parallel to the first plane. A second outer housing contains a second internal volume, and an outlet conduit extends through the second outer housing at a point disposed between the first and second planes.